1. Field of the Invention
The present invention relates to the field of locking mechanisms for controllably locking two assemblies at any relative angular position.
2. Prior Art
A great number of locking devices for controllably locking two assemblies against relative angular rotation are well known in the prior art. Such devices vary considerably depending upon the specific purposes and application of the devices. By way of example, certain devices such as gears provide coupling between two shafts in specific increments of angular orientations. Clutches, on the other hand, may retain two shafts with respect to each other at substantially any relative angular orientation.
In certain applications it is desired to have a simple locking device which may be actuated with a minimum of force and which will lock the respective assemblies at any relative angular orientation. In this regard gear or toothed assemblies provide locking only at specific angular increments, and clutch assemblies are generally relatively mechanically complicated and require substantial actuating force or energy for actuation thereof. Because of the desire for actuation of such mechanisms with the minimum of actuation force, most mechanisms for locking two assemblies against relative angular motion are assemblies providing the desired locking only at specific relative angular orientations between the two assemblies. By way of example, U.S. Pat. No. 2,701,432 discloses a simplified indexing grinding fixture having a simple longitudinally extending pin for engaging any one of a plurality of circumferentially disposed holes in an indexing disc. Another form of indexing device for machine tools is shown in U.S. Pat. No. 2,711,324.
A number of locking devices have been applied to eating utensils such as spoons to provide free rotation of the utensil portion with respect to the handle portion under certain conditions and the locking of the two portions under other conditions. By way of example, in U.S. Pat. No. 2,636,266 a spoon having a rotatable handle is disclosed wherein the spoon becomes locked to the handle at any of a specific plurality of angular orientations under certain conditions and becomes unlocked when the spoon portion is weighted with food. Similarly, in U.S. Pat. No. 2,741,027, infants' spoons are disclosed wherein the utensil portion becomes locked to the handle portion at any of a specific plurality of angular orientations when the assembly is subjected to an axial force.
Another locking device, specifically for a chipping hammer, is disclosed in U.S. Pat. No. 2,429,728, and spoons having a provision for relative angular rotation between the utensil portion and the handle portion are disclosed in U.S. Pat. Nos. 2,682,705 and 2,809,426.
One controllable angular locking device for a power take-off on a marine diesel engine is disclosed in U.S. Pat. No. 3,643,642. In that device one member is provided with a plurality of holes or openings distributed at a radius about an axis of rotation of the assembly. A second member contains a plurality of engaging pins equal in number to the openings in the first member and spaced at the same radius so as to be engageable with the openings in the first member dependent upon the relative axial position between the two members. It will be noted in this assembly that the locking of the two members against relative angular rotation is achieved by the simultaneous engagement of all pins on the second member into all openings in the first member, thereby providing locking against relative angular rotation at a specific number of angular orientations equal in number to the number of pins (or openings) in one of the members.
In addition to the foregoing prior art, devices actuated by the rolling of one or more balls are disclosed in U.S. Pat. Nos. 1,393,312 and 2,950,365, the devices in these two patents being in the form of switches sensitive to the orientation of the devices.